JP3429111B2 - Solid-liquid separation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-head type solid-liquid separation device effective for economically and efficiently filtering a large amount of water such as lakes, ponds, moats, pools and industrial water.

[0002]

2. Description of the Related Art As a filter for purifying lakes, ponds, pools, industrial water, etc., a packed bed type sand filter and a rotary drum type filter using a long hair filter cloth are already known.

However, in such a conventional sand filter, the thickness of the filter layer is usually 100 in the former sand filter.
0 mm, on the other hand, in the latter rotary drum type filter using a long-hair filter cloth, the filter layer has a thickness of 20 to 40 mm, both of which perform solid-liquid separation operation by capturing solid components inside the filter layer. Is.

In these conventional methods, the filtration pressure required for filtration usually requires a high head of about 1 m to 5 m as a head loss, and a pump is usually used to supply raw water to the filter unit.

However, in such a supply system using a pump, when a large amount of water such as lakes, ponds, pools, and industrial water, which is the object of the present invention, is to be treated, the power cost of the pump is increased by increasing the pressure. It is expensive, and as the pressure of the pump increases, the mechanical shearing force applied to the solid components contained in the raw water increases, and the solid components in the liquid to be filtered (raw water) become finer inside the pump and in the transfer pipe, There is a problem that the solid component removal rate by the solid-liquid separation device is reduced.

[0006] In particular, biological flora and fauna of biological systems generated in lakes and ponds, floc flocs generated in industrial water purification process, etc. are vulnerable to such mechanical shearing force and the solid-liquid separation performance is deteriorated, which is a serious problem. Becomes

[0007]

SUMMARY OF THE INVENTION In order to solve these problems, an object of the present invention is to maintain a low filtration pressure without using a pump for supplying raw water to a filtration device, and
To provide a solid-liquid separation device capable of maintaining a high solid component removal rate and a high filtration rate, and capable of efficiently and economically purifying a large amount of raw water such as lakes, ponds, pools, and industrial water. is there.

[0008]

In order to solve the above-mentioned problems, the solid-liquid separation device of the present invention introduces raw water from a raw water reservoir into the inside of a filtration drum having a filter medium mounted on a cylinder, so as to separate the solid-liquid of the raw water by passing the filter medium while rotating the filtration drum
In the solid-liquid separation device, at least the flow path of raw water from the raw water reservoir to the inside of the filtration drum has a head difference.
Based on the flow path that the raw water naturally flows based on,
A coagulant is added to the raw water between the raw water reservoir and the filtration drum.
It is characterized in that a coagulation reaction tank for charging is provided . Raw water between the raw water reservoir and the filtration drum
By adding a flocculant, the solid-liquid components are flocculated and filtered.
The over-efficiency can be improved. This coagulant is
It is preferable to include an on-type polymer flocculant.

[0009]

[0010]

[0011]

[0012]

In the present apparatus, the flow path of the treated water from the filtration drum to the treated water reservoir can be further configured as a flow path in which the treated water naturally flows down based on the head difference. Further, the flow path from the raw water storage pond to the treated water reception pond can be arranged in multiple stages in series.

Further , a pump for returning the treated water from the filtration drum to the raw water reservoir may be provided. After filtration
Since it is treated water, even if a pump is used
There is no problem such as commutation.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the solid-liquid separation device of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to cleaning a pond of a golf course, for example. FIG. 2 shows a cross section of the rotary filtration drum device used in the purification step of FIG. 1 taken in a direction perpendicular to the rotation axis.

In this embodiment, the liquid surface 1 of the upper pond 1 of the golf course is
1 and the water level difference ΔH ₂ between the liquid surface 41 of the lower pond 4 are used to guide the water (raw water) of the upper pond 1 as a raw water storage pond to the filtration drum device by the solid-liquid separation device according to the present invention. The purified water (treated water), excluding solid components, is supplied to the lower pond 4 as a treated water receiving pond.

To explain the configuration of this embodiment, raw water from the upper pond 1 is sent to the coagulation reaction tank 2 as a pretreatment device through the upper pond outflow pipe 12. This aggregation reaction tank 2
A supply line 22 for the coagulant 21 is provided in the vicinity of the inlet of the tank, a burr weir plate 23 is provided on the inflow side, and a baffle plate 24 is provided on the outflow side in the tank 2, and a stirrer is provided between the two plates 23, 24. Two
5 are provided. The muffle weir plate 23 and the outflow-side baffle plate 24 facilitate mixing of the flocculant and the raw water in the flocculation reaction tank 2 to easily generate flocs in the flocculation reaction, and the flocculation agent is short-passed. The added drug is added so that it is not wasted.

The outflow port 26 of the flocculation reaction tank 2 is provided at a lower portion of the tank and communicates with the inflow port of the rotary filtration drum device 3. However, this connecting pipe is not always the agglutination reaction tank 2
Need not be provided at a lower part of the above, and may be located at a position lower than the liquid level 37 in the raw water supply part of the next rotary filtration drum device 3. This is because the liquid level of the flocculation reaction tank 2 and the liquid level 37 of the raw water supply section of the filtration drum device 3 are communicated so that they are substantially the same, and when the raw water moves in the pipe, the flocculated solids are formed. This is because the components are not subjected to mechanical shearing force by a pump or the like and the flocs are not miniaturized, so that solid-liquid separation in the next step can be efficiently performed.

That is, the raw water from the upper pond 1 is introduced into the inside of the rotary filtration drum 31 of the filtration drum device 3 through the upper pond outflow pipe 12, the flocculation reaction tank 2, and its outlet 26. In the purification step, at least the raw water so far is introduced by natural flow based on the head difference ΔH ₃ . Since no pump is used for feeding the liquid up to this point, no mechanical shearing force is applied to the raw water, and the shearing force does not atomize the solid component or the floced solid component due to the addition of the coagulant. . In this state, raw water is introduced into the filtration drum device 3.

The rotary filtration drum device 3 is constructed as a device described in, for example, Japanese Patent Publication No. 4-9081. As will be described with reference to FIGS. 1 and 2, the filtration drum device 3 is provided with a filtration drum 31 having a filter material (filter cloth) 32 attached to the inner surface of the body.
Are rotated by a motor 33. A seal rubber 34 for preventing leakage is provided between the rotatably driven filtration drum 31 and the non-rotating fixed portion. Raw water from the coagulation reaction tank 2 is introduced into the inside of the filtration drum 31, and the raw water passes through the filter medium 32 while rotating the filtration drum 31, whereby the solid-liquid in the raw water is separated. The introduced raw water has a filtration loss head difference ΔH ₁ between the filtering device inflow side liquid level 37 in the filtering drum 31 and the filtering device outflow side liquid level 38 lower than this.
Passes through the filter medium 32 and becomes purified water (treated water),
It is supplied to the lower pond 4 through the outflow pipe 39 from the filtration drum device 3.

The solid component in the raw water is captured by the filter medium 32, and the captured solid component moves to the water surface as the filter drum 31 rotates. The filtered water pumped up,
It is backwashed with the backwash water sprayed from the backwash spray nozzle 35b connected to the filter cloth backwash line 35a. Backwash water
Waste water containing solid components is discharged to the outside of the system through the cleaning water discharge line 36. However, depending on the type of raw water or the filter medium, it may be difficult to sufficiently remove the solid components captured by the filter medium only by backwashing. In this case, the surface washing spray nozzle 35d connected to the filter cloth surface washing line 35c is provided inside the filter drum 31, and the spray nozzle 3
The solid water remaining on the surface side is washed off into the filter drum 31 with surface washing water sprayed from 5d toward the surface of the filter medium,
Filtering through the filter material again is effective in preventing the clogging of the filter material from progressing.

In order to keep the concentration of the solid component in the filtered treated water as low as possible, the direction of the surface washing spray nozzle 35d is changed and the solid component washed off with the surface washing spray water is backwashed and drained. In the same manner as above, it is also possible to receive it in the cleaning drainage water receiving portion 36a at the center of the drum and discharge it to the outside of the system via the cleaning drainage line 36.

The filter medium 32 used in the rotary type filtration drum device 3 has naps of ultrafine fibers having a thickness of 0.1 to 20 μm formed by napping the base material made of woven or knitted material. It lies in one direction and forms a filtration layer. Lying means not standing upright or lying down. The naps on the surface of the woven or knitted material to be the filter medium 32 are usually made of ultrafine synthetic fibers such as polyamide, polyester, polyolefin, polyvinyl alcohol, polyfluoroethylene and polyacrylonitrile having a thickness of 0.1 to 20 μm. Use what you have. The type of weaving or knitting is not particularly limited, but a satin woven fabric is preferable for the woven fabric, and a half knitted tricot fabric is preferable for the knitted fabric because it is easily raised as one means of the napping method.
Ultrafine fibers with a thickness of less than 0.1 μm lack strength and
Fibers having a diameter of more than 0 μm tend to stand upright after being raised, which makes it difficult to form a good filtration layer. For the napped method, a conventionally known means may be used.

The use of such a filter medium is not the only reason that the filter medium is simply suitable for separating phytoplankton such as blue-green algae which often occur in ponds and lakes. As a result of the research conducted by the present inventors, firstly, the fact that the naps of the ultrafine fibers lie in one direction to form the filtration layer as described above means that, in other words, that portion is equivalent to the conventional sand filtration layer. In order to form a dense layer capable of separating fine particles, the filter medium not only removes the phytoplankton, but also agar-like biological slime, which has been a problem in the past, and was aggregated with an aggregating agent. The floc and the like can be efficiently separated. Secondly, the filter medium has a thickness of 1.
Since it is as thin as 5 mm or less, when the target is phytoplankton, which is usually generated in lakes and marshes, and the concentration of suspended matter is about 20 mg / l, the filtration pressure is 6 at the maximum.
This is because it has a feature that it can be suppressed to about 100 mm, and that the filtration rate (amount of treated water) at that time is as high as 900 (m ³ / m ² · day).

By applying a filter medium having such characteristics, it is possible to efficiently capture fine solid components in raw water with a low loss head and at a high speed, and at the same time, the solid components captured are thin because the filter medium is thin. , Back-washing with water spray and surface washing facilitate peeling on the surface of the filter medium, that is, easy cleaning and regeneration of the filter medium, even if used continuously, it will not clog for a long period of time, and the amount of filtered water will be large. Finding the fact that it does not decrease is one of the factors that led to the present invention.

[0026]

The treated water filtered by the filtering drum device 3 as described above is sent to the lower pond 4 as a treated water receiving reservoir through the outflow pipe 39. In the present embodiment, this water supply is also carried out by natural flow based on the head difference without using a pump or the like. In other words, the liquid surface 38 on the outflow side of the filtration drum device 3 and the liquid surface 41 of the lower pond 4 are naturally flown down based on the head difference.

Next, FIG. 3 shows a solid-liquid separator according to another embodiment of the present invention. In this embodiment, the steps from the raw water storage pond to the treated water storage pond are arranged in multiple stages (two stages in this embodiment) in series. The raw water from the raw water storage pond 51 in the first step is solid-liquid separated, and the treated water is treated water receiving pond 5
Sent to 2. The treated water receiving basin 52 of the first stage serves as a raw water storage basin of the second stage, the raw water from the reservoir is subjected to solid-liquid separation, and the treated water is sent to the treated water receiving basin 53.

Raw water from the raw water storage pond 51 is passed through the outflow line 54 and the opening / closing valve 55 to the first-stage filtration drum device 5
The treated water that has been naturally flowed down to the water tank 6 based on the head difference is filtered and temporarily stored in the receiving tank 57. The treated water that overflows from the receiving tank 57 naturally flows down to the treated water receiving reservoir 52 (second-stage raw water storage reservoir). Similarly, the raw water from the treated water receiving reservoir 52 naturally flows down to the filtration drum device 59 through the outflow line 58, and the filtered treated water is received in the receiving tank 60.
After being temporarily stored in the treated water, the treated water overflowing from the receiving tank 60 naturally flows down to the treated water receiving reservoir 53. Receiving tank 5
7 or the receiving tank 60, or both, pump 6
1 or a pump 62 is provided, and a part of the treated water is stored in the raw water reservoir 5
You may make it return to 1.

In this way, taking advantage of the location conditions of each pond,
It is also possible to arrange a plurality of processing steps.

FIG. 4 shows a solid-liquid separator according to still another embodiment of the present invention. In the present embodiment, the raw water of the raw water storage pond 71 is introduced into the filtration drum device 73 floated through the inflow pipe 72 by gravity flow based on the head difference, and the filtered treated water is temporarily stored in the receiving tank 74. After the water is stored, it is returned to the raw water storage pond 71 by the pump 75.

FIG. 5 shows a modification of the apparatus shown in FIG. 4, but in the present embodiment, the apparatus is installed in a lake (in a pond). That is, the raw water of the raw water reservoir 81
Filter drum device 83 installed in the lake through the inflow pipe 82
It is introduced by gravity flow based on the head difference. An atmosphere release pipe 84 extends from the filtration drum device 83 to a position above the liquid surface of the raw water reservoir 81 so as to have a head difference. The filtered treated water is temporarily stored in the receiving tank 85 and then returned to the raw water reservoir 81 by the pump 86.

The treated water thus filtered by the filtering drum devices 73 and 83 may be returned to the raw water storage basins 71 and 81 again. At least a filter drum device 73,
It is possible to prevent the solid component from becoming fine until the filtration treatment by the filtration drum devices 73 and 83 by preventing the raw water from being introduced into 83 before being subjected to mechanical shearing force by a pump or the like.

[0034]

[Examples] Blue-green algae (microcystis) generated in a eutrophication park pond; suspended solid concentration (SS) = 20 mg /
1 [blue water cell number = 2500 cells / ml] is used as raw water, a filter drum using the above-mentioned filter material suitably used in the present invention is provided, and the raw water is introduced and treated by natural flow based on the head difference. The effect of the present invention was confirmed by comparison with the case of using a conventional rapid sand filter.

A filter cloth manufactured by the following method was used as the filter medium of the present invention. In other words, the thickness of 18 cores with polyester as the island component and polystyrene as the sea component is 20μ.
m composite fiber was spun. A spun yarn of 20 / 2S obtained by spinning this composite fiber was used as a weft, and a bundle of 48 polyester fibers having a thickness of 10 μm was used as a warp. The weft was 30 / cm and the warp was 40 / cm. 5 sheets of satin fabric were woven. Furthermore, the polystyrene of the weft yarn was removed from this woven fabric by using trichlorethylene as a solvent, and the thickness was about 2.
About 2000 pieces of 4 μm ultrafine fibers were processed into a woven fabric. Using a raising machine, add 2 to the processed fabric in the warp direction.
Raising is performed 0 times and 10 times in the opposite direction to nap mainly the weft, and has 2.4 μm naps and a nap count of about 1000.
A book / mm napped satin fabric was produced.

The physical properties of this filter cloth were a basis weight of 180 g / m ² and an average opening of 7.5 μm (showing that particles of 7.5 μm can be removed by 50%). On the other hand, in sand filtration, the average diameter of sand particles is 0.64 mm, the uniform coefficient ψ = 1.50,
A packed filter layer having a filter layer thickness of 1000 mm was used.

The test conditions were as follows: the raw water of the above-mentioned constant concentration was supplied while changing the filtration pressure (head loss) from 100 mm to 1600 mm, the time until a certain amount of filtered water was obtained, and the collected constant amount of filtered water. The SS concentration was analyzed, and the removal rate of SS and the filtration rate (amount of treated water) at each filtration pressure were calculated by comparison with the raw water concentration, respectively, and are summarized in FIG. In the figure, A and a are solid-liquid separation according to the present invention,
B and b show comparative example filter media.

As shown in FIG. 6, the influence of the filtration pressure on the SS removal rate of both filter media shows the same behavior characteristics. However, when the filtration pressure exceeds 600 mm of head loss, the particles become finer and the removal rate lowers. Seen. Regarding the filtration rate, the filtration rate of the filter material of the present invention is 5 to 6 times that of the conventional sand filtration. There is also a large difference in the filtration pressure when the head loss is 600 mm or less, preferably 400 mm or less.

From the comparison shown in FIG. 6, in the solid-liquid separation according to the present invention, a pump for transferring raw water was used,
A high filtration rate can be obtained even in a low-loss head area of 600 mm or less. Especially in fields such as ponds, lakes, pools, and industrial water where a large amount of water needs to be filtered, using a pump to transfer water results in extremely high power consumption.
By using the solid-liquid separation device of the present invention, an extremely large economic effect can be obtained. That is, a large amount of raw water can be treated at low cost.

Further, the present invention apparatus, by which can be operated as a filtration pressure even hydrocephalus 600mm or less, as in the present embodiment, the raw water side liquid surface of the solid-liquid separator (upper reservoir of the liquid level 1 in FIG. 1
The difference between 1) and the liquid level on the treated water side (liquid level 41 of the lower pond) is 600.
If the thickness is about mm, the liquid transfer pump is completely unnecessary, and the solid-liquid separation process can be smoothly performed under natural flow.

Further, from FIG. 6, in the above-mentioned embodiment, when the head loss was 600 mm or more, the drive of the liquid feed was excessively applied, and the mechanical shearing force applied to the solid component became large, so that the solid component was miniaturized. The removal rate of SS also decreases. Thus, the solid-liquid separation by the low-loss head as in the present invention is
It can be seen that the method is an efficient method and is an apparatus from the viewpoints of both the removal rate and the power consumption cost for liquid transfer.

Thus, in addition to the above-mentioned ponds, lakes and marshes, the apparatus of the present invention treats especially rivers, dam construction sites and construction spillage at construction sites, and sea reclamation that require treatment of large amounts of water. It is suitable because it has a large economic effect when it is used for treatment of residual water that sometimes occurs.

Further, in the treatment of residual water generated as a supernatant when the sea is filled with seabed dredging sludge or the like, it is common to add two or more kinds of flocculants to treat flocculated flocs after formation. However, by using the method and apparatus of the present invention, it is possible to improve the efficiency by adding an anionic polymer flocculant in a very small amount of about 2 / 10,000 to 5 / 10,000 of raw water SS. It is also known that solid-liquid separation can be performed well, and application to this field is expected to have a large economic effect as well as the effect of preventing pollution of the global environment due to excessive addition of a coagulant.

As the anionic polymer flocculant,
For example, polyacrylamide-based Sunfloc AH-
150P (manufactured by Sanyo Chemical Industry Co., Ltd.), Hymoloc S
S-120 (made by Hymo Co., Ltd.) etc. can be used.

[0045]

As described above in detail, the solid-liquid separation of the present invention
When using a device, a flocculation reaction tank that adds a flocculant to raw water
With the provision of, at least the raw water from the raw water reservoir to the filtration drum is introduced by natural flow based on the head difference, so that mechanical shearing force by a pump or the like can be prevented from acting at least during this period. By suppressing the miniaturization of the solid components in the raw water, a large amount of raw water can be efficiently solid-liquid separated at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a solid-liquid separation device according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of the filtration drum device taken along line II-II in FIG.

FIG. 3 is a schematic configuration diagram of a solid-liquid separation device according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a solid-liquid separator according to still another embodiment of the present invention.

5 is a schematic configuration diagram of a solid-liquid separation device according to a modified example of the device of FIG.

FIG. 6 is a diagram showing the relationship between the SS removal rate, filtration rate (amount of treated water), and filtration pressure (head loss) in Examples and Comparative Examples.

[Explanation of symbols]

1 Upper Pond as Raw Water Reservoir 2 Coagulation Reaction Tank 3 Rotary Filtration Drum Device 4 Lower Pond as Treatment Water Reservoir 11 Upper Pond Liquid Level 12 Upper Pond Outflow Pipe 21 Flocculant 22 Flocculant Supply Line 23 Mug Weir Board 24 Jam Plate 25 Stirrer 31 Filtering drum 32 Filter material (filter cloth) 33 Motor 34 Seal rubber 35 Cleaning pump 35a Filter cloth backwash line 35b Backwash spray nozzle 35c Filter cloth surface wash line 35d Surface wash spray nozzle 36 Wash water discharge line 36a Wash drainage receiver Water part 37 Filtration device inflow side liquid level 38 Filtration device outflow side liquid level 39 Filtration device outflow pipe 41 Lower pond liquid levels 51, 71, 81 Raw water storage reservoir 52 Treated water receiving reservoir (second stage raw water reservoir) 53 Treatment filtration drum introduced from the water受池56,59,73,83 rotary drum filter device [Delta] H ₁ filtered headloss [Delta] H ₂ upper reservoir liquid level and the water head difference lower reservoir liquid level [Delta] H ₃ raw water pond Water head difference of up to

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-6-238110 (JP, A) JP-A-55-111811 (JP, A) JP-A-7-116418 (JP, A) JP-A51- 117450 (JP, A) Actual development Sho 55-88818 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01D 33/06 ZAB

Claims (4)

(57) [Claims] 1. Raw water from a raw water storage pond is introduced into the inside of a filter drum having a filter medium mounted on a cylinder, and the solid liquid in the raw water is passed by passing the filter medium while rotating the filter drum. In a solid-liquid separator designed to separate
In addition, at least the raw water flow path from the raw water reservoir to the inside of the filtration drum is filled with natural water based on the head difference.
It is configured to flow down and the raw water reservoir and the filter are
Coagulation reaction tank that puts a coagulant into raw water between the drum and
A solid-liquid separation device comprising: 2. A process from the filtration drum to the treated water reservoir
The flow path of the treated water naturally flows down the treated water based on the head difference.
The solid-liquid separation device according to claim 1, wherein the solid-liquid separation device is configured in a flow path . 3. The flow from the raw water storage pond to the treated water reception pond
The solid-liquid separation device according to claim 2, wherein the channels are arranged in a plurality of stages in series.
Place 4. The solid-liquid separation device according to claim 1 , further comprising a pump for returning the treated water from the filtration drum to the raw water reservoir .